Losartan potassium also known as 2-butyl-4-chloro-1-(2'-tetrazol-5-yl)-biphenyl-4-yl!methyl!-5-(hydroxymet hyl)imidazole potassium salt has been approved for the treatment of hypertension.
Losartan is known to inhibit the action of the octapeptide hormone angiotensin II (AII) and is useful therefore in alleviating angiotensin induced hypertension. The enzyme renin acts on a blood plasma .alpha..sub.2 -globulin, angiotensinogen, to produce angiotensin I, which is then converted by angiotensin converting-enzyme to AII. The latter substance is a powerful vasopressor agent which has been implicated as a causitive agent for producing high blood pressure in various mammalian species, such as the rat, dog, and man. Losartan inhibits the action of AII at its receptors on target cells and thus prevents the increase in blood pressure produced by this hormone-receptor interaction. By administering losartan to a species of mammal with atherosclerosis and/or high cholesterol and/or hypertension due to AII, the blood pressure is reduced. Losartan is also useful for the treatment of high cholesterol by reducing the total cholesterol. Administration of losartan with a diuretic such as furosemide or hydrochlorothiazide, either as a stepwise combined therapy (diuretic first) or as a physical mixture, enhances the antihypertensive effect of losartan, while also treating atherosclerosis and reducing cholesterol levels. Administration of losartan with a non-steroidal anti-inflammatory drug (NSAID) can prevent renal failure which sometimes results from administration of a NSAID.